the effects of environmental and soil fertility factors on

Pertanika J. Trop. Agric. Sci. 36 (S): 261 - 286 (2013)

ISSN: 1511-3701 © Universiti Putra Malaysia Press

TROPICAL AGRICULTURAL SCIENCEJournal homepage: http://www.pertanika.upm.edu.my/

Article history:Received: 13 August 2012Accepted: 20 September 2012

ARTICLE INFO

E-mail address: [email protected] (Wan Razali, W. M.)* Corresponding author

The Effects of Environmental and Soil Fertility Factors on Plant Species Diversity in Kilim Geoforest Park, Langkawi, Malaysia

G. Fatheen Nabila, Wan Razali, W. M.*, Faridah-Hanum, I. and Arifin Abdu Faculty of Forestry, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

ABSTRACT

Mangroves contain significant biodiversity and are highly valuable for coastal communities for their daily life and ecotourism attractions. It was observed that appropriate environmental and soil factors are important for conducive growth of mangroves, which in turn influence species distribution, composition and diversity. This study was carried out to compare soil fertility status among three main riverine systems and to analyze the effects of environmental and soil fertility factors on species richness, evenness and diversity in mangrove forest at Kilim Geoforest Park in Langkawi. A total of one hundred (20 m × 20 m) plots were established along both sides of the three rivers: River Kisap (40 plots), River Ayer Hangat (30 plots) and River Kilim (30 plots). All the species and trees of diameter 1 cm dbh and above found within the plots were enumerated and identified. Species richness was computed based on the Jackknife method and species diversity using Simpson’s Index, Shannon-Wiener’s Index and Brillouin’s Index. The evenness index was measured by Simpson’s measure of evenness, Camargo’s index of evenness and Smith and Wilson’s index of evenness. The composite soil samples of each riverine system were analysed for available P, dry Ph, total N & C and exchangeable (Ca, K, Mg & Na). The Canonical Component Analysis (CCA) method was used to show the relationship between the environmental and soil fertility factors and plant species diversity. Based on the analysis of the current study, soil fertility factors in the study areas were significantly different among the three rivers. Meanwhile, biodiversity indices like Brillouin’s index, Shannon-Wiener index, Simpson’s index, and Jackknife estimates of species richness were clustered together in River Kisap, as also indicated by the clustering of mangrove species such as Avicennia

marina, Acanthus volubilis, Bruguiera cylindrica, Ceriops decandra, Xylocarpus moluccensis, Rhizophora apiculata and Bruguiera parviflora. Meanwhile, the ordination diagram of canonical redundancy analysis showed strong correlations between

G. Fatheen Nabila, Wan Razali, W. M., Faridah-Hanum, I and Arifin Abdu

262 Pertanika J. Trop. Agric. Sci. 36 (S) 261 - 286 (2013)

environmental and soil fertility factors and species diversity in Kilim Geoforest Park, Langkawi.

Keywords: Mangrove forest, Kilim Geoforest Park

Langkawi, species richness, evenness and diversity,

Jackknife method, Simpson, Shannon-Wiener,

Brillouin, Camargo, Smith and Wilson indices

INTRODUCTION

Mangroves are defined as shrubs, trees, palms or ferns that grow within the inter-tidal region of coastal and estuarine environments throughout the tropical and subtropical areas around the world (Tomlinson, 1986). Mangroves can also include plants, associated forest communities and abiotic factors which form the mangrove ecosystem. The term ‘mangrove’ is also used to define both the plants that occur in tidal forests and to describe the community itself (Tomlinson, 1986; Wightman, 1989). Coastal ecosystems such as estuaries, wetlands and mangrove forests contain significant biodiversity and are highly valuable for coastal communities for their daily life. Mangrove ecosystem attracts intensive attention among the coastal ecosystems due to not only its peculiar habitat characteristics but also its rich biodiversity.

Mangrove forest in Langkawi is unique because they flourish on limestone formation, which is a rare occurrence and also supports unique flora and fauna species, some of which are endemic to the island, particularly the limestone vegetation. They are usually found on a shallow limestone substratum or Type VI of mangrove setting (Thom, 1984), and it is believed as one

of its kinds in the world (Latiff, 2009). However, the anthropogenic pressure often leads to neglect the ecosystem and its surroundings culminate into a critical status of many coastal environments. Mangroves are the most threatened among the coastal ecosystems, more so throughout the tropical developing countries of the world as well as in Langkawi. Mangrove forest in Langkawi was reduced to 3270 ha or 10.6% reduction from 3657.67 ha in 1980 (Latiff, 2009). Knowing the fact that Langkawi is one of the biggest tourist attractions in Malaysia, Kilim Geoforest Park in Langkawi has been rapidly developed since the last 20 years mainly for tourism purposes. The mangrove areas in Kilim Geoforest Park cover approximately 3,142 ha, of which about 1,336 ha belong to Kisap Forest Reserve. There are several threats to Kilim Geoforest Park mangroves, specifically over-exploitation by the local people, such as natural resource development viz. coastal agriculture, salt production, intensive shrimp culture, as well as coastal industrialization and urbanization that completely destroy the mangrove ecosystem; and increasing facilities for yatch parking and activities for ecotourism.

As in other countries, the early attempts at mangrove restoration programmes in Malaysia met with mixed results, with some being successful, while others were doomed from the start. Reports by many experts (Field, 1996; Erftemeijer & Lewis 2000) showed that mangrove restoration programmes conducted before were not based on well-understood ecological


263Pertanika J. Trop. Agric. Sci. 36 (S): 261 - 286 (2013)

principles and well-defined objectives. There are many factors affecting the diversity and composition of mangroves in the world.

In more recent years, attention has turned to the ecological processes that are present in the natural and restored mangrove systems (McKee & Faulkner, 2000; Alongi, 2002; Saenger, 2002; Lewis III, 2005). The relationship between the restored mangrove ecosystem and adjoining ecosystems such as salt marsh (Saintilan & Hashimoto, 1999) and sea grass beds (Hogarth, 2007) has also been a focus of attention. A consensus has also emerged that an understanding of mangrove hydrology is most important for successful restoration (Wolanski et al., 1992). By establishing a new concept aiming at mangrove restoration programmes, degraded mangrove forest would probably be restored.

Of late, however, environmental factors have become the focus of discussion, for example, tidal waters bring nutrients along with other essential minerals to the on-shore region where they become available to mangroves. This tidal water was earlier considered to be the only factor playing a major role in the regeneration and growth of mangroves. Nonetheless, it has been observed that other factors such as rainfall (200cm–300cm), atmospheric humidity (60% - 90%), and moderate temperatures (19°C - 35°C) have also been considered ideal for mangroves’ growth (Blasco, 1977; Naskar & Mandal, 1999).

On the contrary, a study in India showed different results; despite having the maximum tidal fluctuations, Bhabnagar

estuary did not have high mangrove species diversity because of its low average rainfall (60 cm annum-1) and inadequate upstream freshwater supply (Blasco & Aizpuru, 1997). Venkatesan (1966) argued that mangrove habitats would remain productive as long as they got inundated with tidal water, received high rainfall annually, and benefited from the continuous upstream freshwater which usually carries silt, sediments and organic matter. Mandal (1996) supported the above view while investigating seed germination and seedling development of mangroves. Mangroves initially require fresh water to continue their physiological process until they develop salt secretary organs such as salt glands, corkwart, gall and other related mechanisms (Naskar et al., 1997; Naskar & Mandal, 1999).

The objectives of this research were to compare the soil fertility status among the three main riverine systems, to establish interrelationship and relative roles of soil fertility in determining species diversity, as well as to relate environmental factors influencing species distribution, composition and diversity in the three main riverine systems - River Kisap, River Kilim and River Ayer Hangat in the Kilim Geoforest Park, Langkawi, in terms of species richness, evenness and diversity.

MATERIALS AND METHODS

Site Description

Kilim Geoforest Park, Langkawi, features limestone dominating the eastern part of the main Langkawi island and the adjacent small islands of Setul formation. Magnificently



formed landscape of nearly vertical to subrounded karstic hills with pinnacles of various shapes and sizes can be viewed. It comprises three rivers, namely; River Kilim, River Ayer Hangat and River Kisap. These rivers have many tributaries, with mangrove forests line both sides of the rivers. Kilim karstic hills bear many beautiful caves, while karstic coastlines are provided with much more varied and colourful karstic features including sea notches, sea tunnels, sea caves, sea arches, sea stacks and remnant islands. The limestone of Kilim is also very rich in fossils, particularly those at Pulau Langgun. The region’s highest (23m a.s.l.) Holocene (circa 7000m a.s.l) was also recorded within this Geoforest Park. The ecosystems of the old limestone rock formation, the caves, the mudflats and the seas that surround it have three main vegetations, namely; the mangroves, the vegetation of the limestone hills, and the flora of the mudflats and beaches.

The study area is located between the latitude 60 29’ 33.20’’ to 60 23’ 6.24’’ and between the longitude 990 48’ 0.34’’ to 990 55’ 30.86’’ at the northeast of Langkawi Island (Fig.1). The area is mainly covered by forest, mangroves, agricultural land and sand beaches. The topography varies from flat coastal plains to hilly areas to rugged mountains. All the data for this study were collected from November 2009 to February 2010.

Sampling for Plant Composition

Plots of 20 m × 20 m were established along River Kisap (40 plots), River Kilim (30 plots) and River Ayer Hangat (30 plots) within Kilim Geoforest Park. All the plots were 250 m apart from edge to edge of the plot along these rivers to the shoreline (Fig.2).

Within each plot, all trees ≥1 cm dbh (diameter breast height) were identified, measured and recorded. Other parameters recorded were species name and height. All other woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds were counted. However, a complete specimen was collected, tagged and recorded if the species were not known. They were brought to the Herbarium at the Faculty of Forestry, Universiti Putra Malaysia (UPM) for drying process and identification.

Soil Sampling

Soil samples were taken from 6 randomly chosen plots from each of the riverine systems. Within each 20 m × 20 m plot, 5 soil samples were taken – one point (3 soil samples/point) in the middle of the plot, the other four points were collected randomly within each quadrant of the plot. Hence, a total of 90 soil samples were collected using soil auger (10 to 20 cm soil layers) from the three riverine systems. The soil samples from each sampling point plot were mixed thoroughly as a composite sample, air dried and passed through a 2 mm mesh sieve to remove the stone pieces and large root particles. The composite soil sample was used for a detailed soil



analysis, as follows: (i) Available P (ppm); (ii) Dry pH; (iii) Total N (%); (iv) Total organic C (%); (v) Exchangeable Ca (cmol/kg); (vi) Exchangeable K (cmol/kg); (vii) Exchangeable Mg (cmol/kg) and (viii) Exchangeable Na (cmol/kg).

Data Analysis

A data matrix Xij was analyzed, where i= 1, 2, 3,.... 98, 99, 100 denote the 100 plots established along the three rivers, and j= 1, 2, 3...., 19, 20, 21 represent 21 indices of soil fertility, measure of plant diversity and

Fig.1: Location of Kilim Geoforest Park, Langkawi, Malaysia and the sampling site



environmental factors. The j factors are as follows:

1. Environmental factors: (i) Total amount of rainfall (RF); (ii) Total number of raindays (RD); (iii) Mean temperature (T); (iv) Relative humidity (RH); and (v) Surface wind speed (WS)

2. Soil fertility factors: (i) Available P; (ii) Dry pH; (iii) Total N; (iv) Total organic C; (v) Ex. Ca; (vi) Ex. K; (vii) Ex. Mg; (viii) Ex. Na; (Ex. = Exchangeable).

3. Measures of plant diversity: (i) Total number of individual (NI), (ii) Brillouin’s index H (BI), (iii) Shannon-Wiener index of diversity H’ (SW); (iv) Simpson’s index of diversity (SI); (v) Camargo’s index of evenness (CE); (vi) Smith and Wilson’s index of evenness (SW); (vii) Simpson’s measures of evenness (SE); and (viii) Jackknife estimates of species richness (JR).

SAS (Statistical Analysis System) package was used to compare the soil fertility status among the three rivers. In order to investigate complex relationships, the multivariate statistical analysis techniques - Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA) were used. PCA was used to compute the Eigenvalues using Conoco 4.5 software. The CCA method was used to illustrate the interrelationships between the environmental factors, soil fertility and plant diversity groups.

Principle Component Analysis (PCA)

PCA is a useful statistical technique that is used to obtain a small number of linear combinations of the many factors (the 21 factors), which account for the most of the variability in the data. The components with Eigenvalues ≥ 1 and their cumulative percentages of variance are considered

Fig.2: Plot layout at each of the three rivers



as the one accounted for the most of the variability.

Canonical Correlation Analysis (CCA)

CCA is a method to help identify the associations between two sets of variables. It does so by finding linear combinations of the variables in the two sets that exhibit strong correlations. The pair of the linear combinations with the strongest correlation forms the first set of canonical variables. The second set of the canonical variables is the pair of linear combinations that shows the next strongest correlation among all the combinations that are uncorrelated with the first set. Often, a small number of pairs can be used to quantify the relationship of the two sets.

Data for computing species richness, evenness and diversity indices were analyzed using Ecological Methodology Software (Krebbs 1998), as follows:

Species Richness

i. Jackknife Estimate

Where,Ŝ = jackknife estimate of species richnesss = total number of species present in quadratesn = total number of quadrates samplesk = number of unique species (species which occur in only one quadrate)

Species Diversity

i. Simpson’s Index

Where, = Simpson’s index

Pi = proportion of species i in the community

ii. Shannon-Weiner measure

Where,H ‘ = information content of the sample (bits/individual) and index of diversitys = number of speciesPi = proportion of the total sample belonging to i species

iii. Brillouin’s index

HB = ln(N!) - Σln(ni!) N

Where,HB = the Brillouin index, N = total number of individuals in the sampleni = number of individual of species iln(x) = natural logarithm of x (or logarithm base e)N! means the factorial of N = 1 * 2 * 3 * 4... * N



Species Evenness

i. Simpson’s measure of evenness

Where,E1/D = Simpson measure of evennessS = number of species in the sample

= Simpson index

ii. Smith and Wilson’s index of evennessEvar=1-[2/(πarctan{)2/s)}

TABLE 1 Floristic composition and dominant tree species ≥1 cm dbh at Kilim Geoforest Park, Langkawi, Malaysia

Area Family Species No. of Stem

Sungai Kilim

1. Avicenniaceae 1. Avicennia officinalis 202. Rhizophoraceae 2. Bruguiera gymnorhiza 17 3. Bruguiera parviflora 424 4. Bruguiera sexangula 465 5. Ceriops tagal 1264

6. Rhizophora apiculata 1226 7. Rhizophora mucronata 4553. Cycadaceae 8. Cycas siamensis 34. Lythraceae 9. Memecylon edule Roxb. var. ovatum 1 10. Memecylon pauciflorum 15. Rutaceae 11. Murraya paniculata 26. Anacardiaceae 12. Pentaspadon curtisii 38. Moraceae 13. Streblus ilicifolius 19

14. Streblus laxiflorus 19. Polygalaceae 15. Xanthophyllum discolor 810. Meliaceae 16. Xylocarpus granatum 124 17. Xylocarpus moluccensis 18

Total 4051

Where,Evar = Smith and Wilson’s index of evennessni = Number of individuals in species i in the sample (i = 1, 2, ..., s)nj = Number of individuals in species j in the sample (j = 1, 2, ..., s)s = Number of species in the entire sample

iii. Camargo’s index of evenness

Where, pi = proportion of individuals of a species at site i pj= proportion at site j;s = total number of sites in the sample.



Sungai Kisap

1. Avicenniaceae 1. Avicennia marina 552. Rhizophoraceae 2. Bruguiera cylindrica 1110 3. Bruguiera parviflora 311 4. Ceriops decandra 1 5. Ceriops tagal 367

6. Rhizophora apiculata 1114 7. Rhizophora mucronata 2443. Lauraceae 8. Cinnamomun sp. 44. Ebenaceae 9. Diospyros ismailii 215. Elaeocarpaceae 10. Elaeocarpus griffithii 16. Erythroxylaceae 11. Erythroxylum cuneatum 97. Euphorbiaceae 12. Excoecaria agallocha 48. Loganiaceae 13. Fagraea curtisii 79. Bignoniaceae 14. Fernando adenophylla 1010. Moraceae 15. Ficus deltoidea 5 16. Ficus rumpii 2 17. Ficus superb 411. Flacourtiaceae 18. Flacourtia rukam 312. Sterculiaceae 19. Heritiera littoralis 413. Flacourtiaceae 20. Hydnocarpus ilicifolia 414. Lythraceae 21. Lagerstroemia floribunda 915. Euphorbiaceae 22. Macaranga sp. 1 23. Mallotus brevipetiolatus 4 24. Mallotus dispar 2

25. Phyllanthus pulcher 1516. Lythraceae 26. Memecylon edule Roxb. var. ovatum 18 27. Memecylon pauciflorum 3517. Tiliaceae 28. Microcos sp. 1 29. Pentace sp. 318. Anacardiaceae 30. Pentaspandon curtisii 9 31. Pentaspandon velutinis 119. Rubiaceae 32. Psychotria angulata 1

cont’d Table 1



Sungai Kisap

20. Sterculiaceae 33. Pterospermum lanceaefolium 521. Bignoniaceae 34. Radermachera pinnata 11 35. Radermachera stricta 322. Araliaceae 36. Schefflera heterophylla 223. Bignoniaceae 37. Spatodea companulata 924. Anacardiaceae 38. Spondias pinnata 225. Sterculiaceae 39. Sterculia augustifolia 17 40. Sterculia lancaviensis 1926. Moraceae 41. Streblus ilicifolius 4127.Myrtaceae 42. Syzgium sp. 328. Combretaceae 43. Terminalia triptera 529. Verbenaceae 44. Vitex pinnata 130. Polygalaceae 45. Xanthophyllum affine 3 46. Xantophyllum discolor 331. Meliaceae 47. Xylocarpus granatum 253 48. Xylocarpus moluccensis 76

Total 3832

Sungai Ayer Hangat

1. Avicenniaceae 1. Avicennia marina 372. Rhizophoraceae 2. Bruguiera cylindrical 62 3. Bruguiera parviflora 91

4. Ceriops tagal 429 5. Rhizophora apiculata 1109

6. Rhizophora mucronata 2653. Ebenaceae 7. Diospyros ferrea 14. Euphorbiaceae 8. Excoecaria agallocha 15. Moraceae 9. Ficus superb 16. Anacardiaceae 10. Pentaspadon motley 18. Lythraceae 11. Sonneratia alba 19. Moraceae 12. Streblus ilicifolius 510. Polygalaceae 13. Xanthophyllum affine 411. Meliaceae 14. Xylocarpus granatum 1517 15. Xylocarpus moluccensis 27 16. Xylocarpus rumphii 54 Total 3605 Grand Total 11488

cont’d Table 1



RESULTS AND DISCUSSION

Overall Species Composition and Dominance

In this study, a total of 11,488 and 14,820 individual species of trees ≥1 cm dbh and other woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds were identified, measured and recorded, respectively. All the species were enumerated to determine species composition and

dominance in the 4 hectares study plot at Kilim Geoforest Park, Langkawi. The identified species were further classified according to their family and number of stems. For each riverine system, at least 24 families, 37 genera and 58 species of all trees (Table 1) were identified, apart from 43 families, 88 genera and 114 species of non-trees (e.g., orchids, shrubs, climbers, epiphytes, grasses, bamboos, and weeds (Table 2).

TABLE 2 The floristic composition and dominant species of woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds at Kilim Geoforest Park, Langkawi, Malaysia

Area Family Species No. of Stem

Sungai Kilim

1. Acanthaceae 1. Acanthus volubilis 402. Euphorbiaceae 2. Euphorbia antiquorum 233. Meliaceae 3. Xylocarpus granatum 66 4. Xylocarpus moluccensis 274. Moraceae 5. Streblus ilicifolius 455. Polygalaceae 6. Xanthophyllum discolor 46. Rhamnaceae 7. Ziziphus affinis 137. Rhizophoraceae 8. Bruguiera parviflora 127 9. Bruguiera sexangula 256 10. Ceriops tagal 439 11. Rhizophora apiculata 759 12. Rhizophora mucronata 118

Total 1917

Sungai Kisap

1. Acanthaceae 1. Acanthus ebracteatus 3 2. Acanthus ilicifolius 68 3. Acanthus volubilis 679 4. Justicia sp. 6 5. Pseuderanthemum crenulatum 62. Aizoaceae 6. Sesuvium portulacastrum 53. Anacardiaceae 7. Pentaspadon curtisii 1 8. Pentaspadon motleyi 74. Annonaceae 9. Fissistigma fulgen 635. Apocynaceae 10. Parameria sp. 30



Sungai Kisap

6. Araliaceae 11. Schefflera heterophylla 5 12. Scindapsus scortechinii 37. Araceae 13. Alocasia denudate 79 14. Amorphophallus haematospadix 12 15. Amorphophallus variabilis 60 16. Arisaema fimbriatum 2868. Asclepiadaceae 17. Hoya coronaria 4 18. Hoya diversifolia 73 19. Pentasacme caudatum 159. Asteracae 20. Chromolaena odorata 37

21. Pluchea indica 110. Avicenniaceae 22. Avicennia marina 8511. Begoniaceae 23. Begonia curtisii 169 24. Begonia phoeniogramma 312. Cycadaceae 25. Cycas siamensis 113. Cyperaceae 26. Fimbristylis calcicola 614. Davalliaceae 27. Davallia denticulate 4415. Dioscoreaceae 28. Dioscorea calcicola 53 29. Dioscorea tamarisciflora 18516. Dryopteridaceae 30. Dryopteris anneaphylla 36 31. Dryopteris ludens 51 32. Tectaria coadunata 8 33. Tectaria keckii 1917. Ebenaceae 34. Diospyros ferrea 33 35. Diospyros ismailii 818. Euphorbiaceae 36. Croton cascarilloides 58

37. Excoecaria agallocha 638. Macaranga sp. 339. Mallotus brevipetiolatus 240. Mallotus dispar 1141. Phyllanthus columnaris 542. Phyllanthus pulcher 9

19. Flacourtiaceae 43. Flacourtia rukam 120. Gesneriaceae 44. Boea acutifolia 52

45. Didymocarpus lacunosus 1246. Henklia sp. 14647. Monophyllaea glabra 3348. Paraboea ferruginea 128

21. Gramineae 49. Dendrocalamus elegans 522. Labiatae 50. Orthosiphon aristatus 1423. Leguminosae 51. Bauhinia curtisii 40

cont’d Table 2



52. Bauhinia flava 22

Sungai Kisap

53. Caesalpinia crista 26 54. Derris trifoliata 13 55. Mucuna gigantea 1524. Loganiaceae 56. Fagraea curtisii 6025. Lythraceae 57. Lagerstroemia floribunda 3 58. Memecylon edule 130 59. Memecylon pauciflorum 226. Meliaceae 60. Xylocarpus granatum 605 61. Xylocarpus moluccensis 10827. Menispermaceae 62. Stephania venosa 3

Sungai Kisap

63. Tinospora crispa 928. Moraceae 64. Ficus deltoidea 14 65. Streblus ilicifolius 155 66. Streblus laxiflorus 5429. Oleaceae 67. Jasminum insularum 7530. Orchidaceae 68. Bulbophyllum vaginatum 14 69. Bulbophyllum xanthum 5 70. Dendrobium gemellum 3 71. Dendrobium pachyglossum 6 72. Eria bractescens 25 73. Eulophia keithii 12 74. Flickingeria fimbriata 42 75. Geodorum citrinum 3 76. Liparis elegans 17 77. Nervilia calcicola 428 78. Vandopsis gigantea 1631. Polypodiaceae 79. Drynaria quercifollia 55 80. Drynaria sparsisora 43 81. Microsorum punctatum 80 82. Microsorum zippelii 20 83. Phymatosorus nigrescens 6 84. Pyrrosia lanceolata 2 85. Pyrrosia piloselloides 10 86. Selliguea sp. 10032. Pteridaceae 87. Acrostichum aureum 1133. Rhamnaceae 88. Ventilago oblongifolia 8

cont’d Table 2



Sungai Kisap

89. Ziziphus affinis 16 90. Ziziphus oenoplia 10034. Rhizophoraceae 91. Bruguiera cylindrica 809 92. Bruguiera parviflora 273 93. Ceriops tagal 455 94. Rhizophora apiculata 1316 95. Rhizophora mucronata 12135. Rubiaceae 96. Antirhea atropurpurea 61 97. Argostemma pictum 137 98. Psychotria angulata 18 99. Psydrax sp. 4736. Rutaceae 100. Micromelum minutum 71 101. Murraya koenigii 27 102. Murraya paniculata 937. Sapindaceae 103. Allophylus ternatus 2638. Selaginellaceae 104. Selaginella sp. 58039. Tiliaceae 105. Microcos sp. 3240. Verbenaceae 106. Cissus repens 71 107. Clerodendrum nutans 841. Vitaceae 108. Tetrastigma leucostaphylum 4 109. Vitex siamica 442. Zingiberaceae 110. Kaempferia pulchra 15

Total 9069

Sungai Ayer Hangat

1. Acanthaceae 1. Acanthus ebracteatus 78 2. Acanthus ilicifolius 162 3. Acanthus volubilis 6602. Avicenniaceae 4. Avicennia marina 293. Lythraceae 5. Memecylon edule 44. Meliaceae 6. Xylocarpus granatum 702 7. Xylocarpus moluccensis 77 8. Xylocarpus rumphii 765. Moraceae 9. Ficus deltoidea 36. Rhamnaceae 10. Ziziphus affinis 27. Rhizophoraceae 11. Bruguiera cylindrica 24 12. Bruguiera parviflora 69 13. Ceriops tagal 713 14. Rhizophora apiculata 1174 15. Rhizophora mucronata 568. Rubiaceae 16. Psydrax sp. 5 Total 3834 Grand Total 14820

cont’d Table 2



For trees ≥1 cm dbh as in Table 1, five most dominant species at each riverine system in terms of the number of stems are as follows:

Sg. Kilim: Ceriops tagal (1264 stems), Rhizophora apiculata (1226), Bruguiera sexangula (465), Rhizophora mucronata (455 stems), and Bruguiera parviflora (424 stems);

Sg. Kisap: Rhizophora apiculata (1114 stems), Bruguiera cylindrical (1110 stems); Ceriops tagal (367 stems), Bruguiera parviflora (311 stems); and Rhizophora mucronata (244 stems); and

Sg. Ayer Hangat: Xylocarpus granatum (1517 stems), Rhizophora apiculata (1109 stems), Ceriops tagal (429 stems), Rhizophora mucronata (265 stems); and Bruguiera parviflora (91 stems).

Meanwhile, the two most dominant families for trees ≥1 cm in the three riverine systems combined are Rhizophoraceae (8954 stems or 77.94% of the total stems) and Meliaceae (2069 stems or 18.01%). Rhizophoraceae has 8 species in 3 genera (8954 stems or 77.94%), the highest, and therefore, the most diverse among the trees ≥1 cm in the three riverine systems. This is followed by Moraceae (5 species in 1 genus: 78 stems or 0.68%) and Euphorbiaceae (5 species in 4 genera: 27 stems or 0.24%). On the other hand, the least diverse plant species were those with only one genus and one species in various families, while the most were with less that 10 individual stems.

For woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds, five most dominant species at each riverine system in

terms of the number of stems are as follows (Table 2):

Sg. Kilim: Rhizophora apiculata (759), Ceriops tagal (439 stems), Bruguiera sexangula (256), Bruguiera parviflora (127 stems) and Rhizophora mucronata (118 stems);

Sg. Kisap: Rhizophora apiculata (1316 stems), Bruguiera cylindrical (809 stems); Acanthus volubilis (679 stems), Ceriops tagal (455 stems), and Bruguiera parviflora (311 stems); and

Sg. Ayer Hangat: Rhizophora apiculata (1174 stems), Ceriops tagal (713 stems), Xylocarpus granatum (702 stems), Acanthus volubilis (660 stems), and Xylocarpus moluccensis (77 stems).

The three most dominant families for plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds in the three riverine systems combined were Rhizophoraceae (6709 stems or 45.27% of the total stems), Acanthaceae (1702 stems or 11.48%) and Meliaceae (1661 stems or 11.21%). Orchidaceae has 11 species in 9 genera (571 stems or 3.85%), the highest and therefore, the most diverse for plants ≤ 1cm dbh in the three riverine systems. This is followed by Euphorbiaceae (9 species in 7 genera: 124 stems or 0.84%), Polypodiaceae (8 species in 5 genera: 316 stems or 2.13%), Rhizophoraceae (6 species in 3 genera: 6709 stems or 45.27%) and Gesneriaceae (5 species in 5 genera: 371 stems or 2.5%). On the other hand, the least diverse plant species are those with only one genus and one species in various families and the majority is with less 75 stems.



The Effect of Soil Fertility and Environmental Factors on Plant Species Diversity

Environmental factors for the year 2010, such as RF, RD, T, RH collected from a nearby meteorological station, are similar for all the study areas, namely; RF= 2398.2 mm, RD=180 days, T= 28.4 0C, RH= 78.8 % and WS=1.9 m/second, as the rivers are adjacent to each other.

The soil fertility factors in the three study areas (River Kisap, River Kilim and River Ayer Hangat) were also determined in this study. Many previous studies have shown that soil fertility is one of the key factors determining the species diversity in certain areas (Zack et al., 2003). Based on our analysis, some soil fertility factors in the study areas are significantly different among the three rivers (Table 3).

The soil fertility factors are closely related to soil organic matter (SOM) content and its mineralization. The extent of C mineralization determines soil nutrient release and therefore nutrient availability.

In the study area, soil properties showed a slight heterogeneity among the study sites. The test results in Table 3 show that River Kisap has higher available P, total N and organic C contents as compared to River Kilim and River Ayer Hangat.

Analysis of the Plant Species Diversity

Interestingly, species richness, species heterogeneity and species evenness for both mangrove and woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds for the three locations showed that they are significantly diverse (Tables 4 and 5). Based on Jackknife’s index, River Kisap, with an index equals to 53.32 and 126.85, is the richest area with mangrove and woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds, respectively as compared to River Ayer Hangat and River Kilim. In the River Kisap area, 15 mangrove species were identified, whereas only 8 species were identified at the other two rivers.

TABLE 3 Soil fertility factors at the three riverine systems at Kilim Geoforest Park, Langakwi, Malaysia (statistics sharing the same superscripts (a or b) are not significantly different at P > 5%)

Soil Fertility FactorsLocations

River Ayer Hangat River Kilim River KisapAvailable P (ppm) 153.94a 148.59a 166.07b

Total N (%) 0.27a 0.28a 0.29a

Total 0rganic C (%) 4.14a 6.21a 6.93b

Ex. Ca (cmol/kg) 8.22a 11.48a 8.80a

Ex. K (cmol/kg) 2.30a 2.61a 2.60a

Ex. Mg (cmol/kg) 21.53a 30.91b 22.70a

Ex. Na (cmol/kg) 54.34a 79.23b 57.62a

Soil pH 5.83 5.28 6.04



TABLE 4 Species diversity of mangrove at three riverine systems in Kilim Geoforest Park, Langkawi

A. Measure of Species RichnessDiversity Index River Kilim River Kisap River Ayer Hangat

Jackknife estimates of species richness 19.48 53.32 18.32

B. Measure of Species Heterogeneity

Diversity Index River Kilim River Kisap River Ayer Hangat

Simpson’s index of diversity (1-D) 0.77 0.81 0.70

Shannon-Wiener index of diversity H’ 2.44 3.00 2.08

Brillouin index of diversity 2.43 2.97 2.07

C. Measure of Species Evenness

Diversity Index River Kilim River Kisap River Ayer Hangat

Simpson’s measure of evenness 0.26 0.11 0.21

Camargo’s index of evenness 0.25 0.14 0.22

Smith and Wilson’s Index of Evenness 0.10 0.18 0.10

TABLE 5 Species diversity of woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds at three riverine systems in Geoforest Park, Langkawi, Malaysia

A. Measure of Species RichnessDiversity Index River Kilim River Kisap River Ayer HangatJackknife estimates of species richness 13. 57 126.85 17.76B. Measure of Species HeterogeneityDiversity Index River Kilim River Kisap River Ayer HangatSimpson’s index of diversity (1-D) 0.76 0.95 0.81Shannon-Wiener index of diversity H’ 2.55 5.11 2.72Brillouin index of diversity 2.53 5.07 2.71C. Measure of Species EvennessDiversity Index River Kilim River Kisap River Ayer HangatSimpson’s measure of evenness 0.35 0.17 0.32Camargo’s index of evenness 0.37 0.25 0.32Smith and Wilson’s Index of Evenness 0.29 0.23 0.16



Based on the recorded data, all the indices showed that Sungai Kisap is the most diverse area in Kilim Geoforest Park, followed by Sungai Kilim and Sungai Ayer Hangat. As for woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds, the ranking is as follows: Sungai Kisap > Sungai Ayer Hangat > Sungai Kilim. Sungai Kilim showed the most evenness area for both mangroves and woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds, followed by Sungai Ayer Hangat and Sungai Kisap.

The Relationships between Environmental Factors and Measures of Plant Diversity

Tables 6 and 7 summarize the Eigenvalues, species-environment correlation and cumulative percentage variance of the species data and species-environment relation obtained through CCA. The results of the interaction of mangrove species with the environmental factors are explained at the first and second axis of canonical correlation. High Eigenvalues (0.317) and species-environment correlations (r =1.00) were obtained at the first axis. At

TABLE 6 A summary of RDA ordination for mangrove tree species and their relationship with environmental factors in the Kilim Geoforest Park, Langkawi, Malaysia

TermAxis

Total inertia1 2 3 4

Eigenvalues: 0 .317 0.228 0.000 0.000 0.546Species-environment correlations: .000 1.000 0.000 0.000Cumulative percentage variance of species data : 58.2% 100% 0.0 0.0 of species-environment relation: 58.2% 100% 0.0 0.0Sum of all eigenvalues: 0.546Sum of all canonical eigenvalues : 0.546

TABLE 7 A summary of the RDA ordination for woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds and their relationship with environmental factors in the Kilim Geoforest Park, Langkawi, Malaysia

TermAxes

Total inertia1 2 3 4

Eigenvalues : 0.418 0.152 0.000 0.000 0.570Species-environment correlations: 1.000 1.000 0.000 0.000Cumulative percentage variance of species data : 73.3% 100% 0.0 0.0 of species-environment relation: 73.3% 100% 0.0 0.0Sum of all eigenvalues 0.570Sum of all canonical eigenvalues 0.570



the second axis, however, the Eigenvalues decreased (0.228), with species-environment correlation value was maintained. These values proved that the environmental factors strongly influenced species diversity in the study areas.

The ordination diagrams of canonical redundancy analysis (RDA) shown in Fig.3 and Fig.4 indicate a strong correlation between environmental factors and species diversity in Kilim Geoforest Park, Langkawi. Mangrove species such as AM, AV, BC, CD, XM, RA and BP were clustered together in the River Kisap area. This is

due to the best soil fertility factors such as soil pH, available P (AP), total N (N), total organic C (OC), ex. K (eK), ex. Ca (eCa), ex. Mg (eMg), and ex. Na (eNa) induced by favourable environmental factors such as RF, RD, T, RH. Moreover, plant vigour variables such as dbh (DBH), height, basal area (BA) and the number of individual (N) also showed a strong correlation with soil fertility in the study areas (Fig.3).

By using the ordination diagram, it clearly shows that River Kisap is the most diverse area in the Kilim Geoforest Park, Langkawi. Many biodiversity indices such

Fig.3: Ordination diagram of the first two axes of RDA for the mangrove species and their relationship with environmental factors in the Kilim Geoforest Park, Langkawi, Malaysia (see Appendix 1 for list of acronyms)



as Brillouin’s index H (BI), Shannon-Wiener index of diversity H’ (SW), Simpson’s index of diversity (SI), and Jackknife estimates of species richness (JR) were clustered together in River Kisap (Fig.3 and Fig.4).

CONCLUSION

Plant biodiversity provides a buffer against environmental fluctuations, because different species respond differently to these fluctuations, leading to more predictable aggregate community or ecosystem properties (Loreau et al., 2001). In the present study, the interrelationship and relative roles of soil fertility and environmental factors have been investigated to determine the effect to which they influence species

distribution, composition and diversity in the three main rivers, namely; River Kisap, River Kilim and River Ayer Hangat in Kilim Geoforest Park, Langkawi. Multivariate statistical analysis techniques (PCA and its RDA ordination, CCA) were used to understand their relationships. The study area is also characterized by complex topography and heterogeneous vegetation.

Results from RDA and CCA indicate that soil fertility and environmental factors should be considered in explaining variability in plant diversity. It is a fact that organic matter is a critical factor in determining the status of soil fertility in a certain area. In the present study, River Kisap is found to be more fertile than River Kilim and River Ayer Hangat because it has

Fig.4: Ordination diagram of the first two axes of RDA for woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds and their relationship with environmental factors in the Kilim Geoforest Park, Langkawi, Malaysia (see Appendix 1 for list of acronyms)



higher content of organic C and available P, as well as suitable soil pH for the growth of vegetation. Hence, River Kisap is the most diverse area in terms of floristic composition as compared to River Kilim and River Ayer Hangat. Meanwhile, variation in diversity is often correlated with productivity, and also with many other factors that influence productivity such as soil fertility, climate, disturbance regime or herbivory (Loreau et al., 2001). Understanding how these atmospheric and climatic change factors may interact with one another is important because their interactions may affect individual, community and ecosystem level processes in previously unpredicted ways (Long, 1991; Morrison & Lawlor, 1999; Poorter & Pe´rez-Soba, 2001). The response of plant communities to the changes in resource availability is often mediated by species composition, particularly given the range of growth strategies, demography and productivity possessed by diverse plant communities (Niklaus et al., 2001; Reich et al., 2004).

Kilim Geoforest Park, Langkawi, is very sensitive, and it is also a protected area because it has been declared by UNESCO as one of the world heritage (UNESCO 2000). The diversity of the biological resources of this area provides direct economic benefits to the local people. This biological diversity provides timber and non-timber goods in the forestry sector, food and industrial crops in the agricultural sector, as well as food in the fisheries sector and for tourism attraction.

According to Malaysia’s National Policy on Biological Diversity (2010)

report, agriculture, forestry and fisheries have been major contributors to national wealth creation. The tourism industry relies on the country’s diverse and unspoilt natural beauty including unique species of plants and animals in national parks, wildlife reserves, bird parks and in marine parks and the adjacent coral reefs. Kilim Geoforest Park, Langkawi, stands to gain due to the diversity of its biological resources.

ACKNOWLEDGEMENTS

The study was financially supported by the Research University Grant Scheme (RUGS), Universiti Putra Malaysia (03-01-07-0037RU).

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APPENDIX I List of Acronyms

Acronym Mangrove Species ≥1 cm dbh Acronym Environmental/ Metereological Data

AE Acanthus ebracteatus RF Total Amount of rainfall

AI Acanthus ilicifolius RD Total number of rainy days

AM Avicennia marina T 24 hour mean temperature

AO Avicennia officinalis RH 24 hour mean relative humidity (%)

AV Acanthus volubilis WS Mean surface wind speed

BC Bruguiera cylindrica

BG Bruguiera gymnorrhiza Soil FertilityFactors

BP Bruguiera parviflora P Available P

BS Brugueira sexangula pH Dry pH

CD Ceriops decandra N (%) Nitrogen

CT Ceriops tagal C (%) Organic Carbon

RA Rhizophora apiculata EC Exchangeable Calcium

RM Rhizophora mucronata EK Exchangeable Potassium

XG Xylocarpus granatum EM Exchangeable Magnesium

XM Xylocarpus moluccensis EN Exchangeable Natrium

XR Xylocarpus rumphii Woody plants ≤ 1cm dbh, shrubs, climbers, epiphytes and weeds Measures of Plant Species Diversity

AC Acrostichum aureum NI Total number of individual

At Allophylus ternatus BI Brillouin’s index H

Ad Alocasia denudata SW Shannon-Wiener index of diversity

Ah Amorphophallus haematospadix SI Simpson’s index of diversity (1-D)

Av Amorphophallus variabilis CE Camargo’s index of evenness E’

Aa Antirhea atropurpurea SWE Smith and Wilson’s index of evenness

Ap Argostemma pictum SE Simpson’s measures of evenness E1/D

Af Arisaema fimbriatum JR Jackknife estimates of species richness

Am Avicennia marina

Bc Bauhinia curtisii Other parameters

Bf Bauhinia flava DBH Total DBH (cm)

Bc Begonia curtisii tDBH Mean total DBH (cm)

Bp Begonia phoeniogramma BA Total Basal Area (m2)

Bs Boea acutifolia

Cc Caesalpinia crista

Cr Cissus repens

Cn Clerodendrum nutans



Co Chromolaena odorata Md Mallotus dispar

Cca Croton cascarilloides Me Memecylon edule

Cs Cycas siamensis Mp Memecylon pauciflorum

Dd Davallia denticulata M Microcos sp.

Dg Dendrobium gemellum Mm Micromelum minutum

Dp Dendrobium pachyglossum Mp Microsorum punctatum

De Dendrocalamus elegans Mz Microsorum zippelii

Dt Derris trifoliata Mg Monophyllaea glabra

Dl Didymocarpus lacunosus Mgi Mucuna gigantea

Dc Dioscorea calcicola Mk Murraya koenigii

Dt Dioscorea tamarisciflora Mp Murraya paniculata

Df Diopsyros ferrea Nc Nervillia calcicola

Di Diopsyros ismailli Oa Orthosiphon aristatus

Dq Drynaria quercifolia Pf Paraboea ferruginea

Ds Drynaria sparsisora P Parameria sp.

Da Dryopteris anneaphylla Pc Pentasacme caudatum

Dl Dryopteris ludens Pcu Pentaspadon curtisii

Eb Eria bractescens Pm Pentaspadon motleyi

Ek Eulophia keithii Pc Phyllanthus columnaris

Ea Euphorbia antiquorum Pp Pyllanthus pulcher

Eag Excoecaria agallocha Pi Pluchea indica

Fc Fagraea curtisii Pc Pseuderanthemum crenulatum

Fd Ficus deltoidea Pa Psychotria angulata

Fc Fimbristylis calcicola Psy Psyndrax sp.

Ff Fissistigma fulgen Pl Pyrrosia lanceolata

Fr Flacourtia rukam Ppi Pyrrosia piloselloides

Ff Flickingeria fimbriata Sh Schefflera heterophylla

Gc Geodorum citrinum Ss Scindapsus scortechinii

H Henklia sp. S Selaginella sp.

Hc Hoya coronaria Se Selligue sp.

Hd Hoya diversifolia Sp Sesuvium portulacastrum

Ji Jasminum insularum Sv Stephania venosa

Js Justicia sp. Si Streblus ilicifolius

Kp Kaempferia pulchra Sl Streblus laxiflorus

Lf Lagerstroemia floribunda Tc Tectaria coadunata

Le Liparis elegans Tk Tectaria keckii

M Macaranga sp. Tl Tetrastigma leucostaphylum

Mb Mallotus brevipetiolatus Tc Tinospora crispa



Vg Vandopsis gigantea

Vo Ventilago oblongifolia

Vs Vitex siamica

Xd Xanthophyllum discolor

Xg Xylocarpus granatum

Za Ziziphus affinis

Zo Ziziphus oenoplia

the effects of environmental and soil fertility factors on

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